The Interaction Between Neonatal Fc Receptor With IgG And IgG Trantsport Across Mucosal Membrane By Neonatal Fc Receptor

The Fc receptors of immunoglobulin is the cell surface molecules binding the Fc of immunoglobulin.The receptors experss in a variety of immune cells,such as,macrophages,monocytes,neutrophils,eosinophils,NK cells,et al.The Fc combine with the NK cell –based Innate immune cell surface receptor to kill pathogens playing a role of immune response.Mammals in just after the birth,the immune system function are not yet perfect,so that it is very important to obtain passive immunization.The newborns to obtain the mother’s specific humoral immune dependent on transporting maternal IgG from mother to newborn.Maternal lgG in the process of milk secretion and uptaked by newborns need the neonatal Fc receptor,the cell transfer effect through the epithelial barrier.Known FcRn are expressed in the placenta,intestinal epithelial cells,endothelial cells,breast,lung tissue,kidney tissue,liver and so on.FcRn in IgG cross-intestinal mucous membrane transport and the protection of serum IgG from degradation,playing a very important role.Because of FcRn combination CH2~CH3 hinge region of Fc fragment is highly conserved,so in this study,using the protein interaction array system to determine the dynamics of interaction the human IgG,bovine IgG,sheep IgG,horse IgG,rabbit IgG with recombinant human FcRn,determining the binding constant KD.At the same time,oral administration of heterologous antibody in mice and then venous blood to detect whether heterologous antibodies cross through the mucous membrane by the intestinal epithelial cells FcRn enter into the blood circulation by complement fixatueion test.The protein interaction array system measured,human IgG,cattle IgG,sheep IgG,horse IgG and rabbit IgG combined with human FcRn binding constant KD,respectively.In comparison,the affinity of the rabbit and human FcRn is strongest.Complement fixation test results show that heterologous antibodies by oral administration under the transporter role of FcRn in intestinal epithelial cells enter into the blood circulation.These studies will provide the basis for immune milk and infant formula added heterologous IgG.At the same time,also provide theoretical basis for the integration of the antibody for tumor therapy.